CLIMATE CHALLENGESWhy This Summer Might Bring the Wildest Weather Yet

By Sachi Kitajima Mulkey

Published 11 June 2024

Summers keep getting hotter, and the consequences are impossible to miss: In the summer of 2023, the Northern Hemisphere experienced its hottest season in 2,000 years. Forecasts suggest that this year’s upcoming “danger season” has its own catastrophes in store. El Niño has been rough, but its departure could be even rougher.

Summers keep getting hotter, and the consequences are impossible to miss: In the summer of 2023, the Northern Hemisphere experienced its hottest season in 2,000 years. Canada’s deadliest wildfires on record bathed skylines in smoke from Minnesota to New York. In Texas and Arizona, hundreds of people lost their lives to heat, and in Vermont, flash floods caused damages equivalent to those from a hurricane. 

Forecasts suggest that this year’s upcoming “danger season” has its own catastrophes in store. On May 23, scientists from the National Oceanic and Atmospheric Administration announced that the 2024 Atlantic hurricane season could be the most prolific yet. A week earlier, they released a seasonal map predicting blistering temperatures across almost the entire country

One driving force behind these projections are the alternating Pacific Ocean climate patterns known as El Niño and La Niña, which can create huge shifts in temperature and precipitation across the North and South American continents. After almost a year of El Niño, La Niña is expected to take the reins sometime during the upcoming summer months. As climate change cooks the planet and the Pacific shifts between these two cyclical forces, experts say the conditions could be ripe for more extreme weather events.

“We’ve always had this pattern of El Niño, La Niña. Now it’s happening on top of a warmer world,” said Zeke Hausfather, a climate scientist at Berkeley Earth, an environmental data science nonprofit. “We need to be ready for the types of extremes that have not been tested in the past.”

During an El Niño, shifting trade winds allow a thick layer of warm surface water to form in the Pacific Ocean, which, in turn, transfers a huge amount of heat into the atmosphere. La Niña, the opposite cycle, brings back cooler ocean waters. But swinging between the two can also raise thermostats: Summers between the phases have higher-than-average temperatures. According to Hausfather, a single year of El Niño brings the same heat that roughly a decade of human-caused warming can permanently add to the planet. “I think it gives us a little sneak peek of what’s in store,” he said.